Metal phosphate-containing catalysts and preparation

ABSTRACT

A HYDROTREATING CATALYST CONSISTING ESSENTIALLY OF A POROUS XEROGEL CONTAINING (A) TUNGSTEN, IN THE FORM OF METAL, METAL OXIDE, METAL SULFIDE, OR ANY COMBINATION THEREOF, IN AN AMOUNT OF 5 TO 25 WEIGHT PERCENT OF SAID XEROGEL, CALCULATED AS METAL; (B) DISCRETE SUBSTANTIALLY INSOLUBLE METAL PHOSPHATE PARTICLES (1) BEING DISPERSED IN SAID XERGEL, (2) CONSISTING OF AT LEAST ONE METAL PHOSPHATE SELECTED FROM PHOSPHATES OF TITANIUM ZIRCONIUM, THORIUM, TIN, HAFNIUM AND CERIUM, AND (3) CONTAINING PHOSPHORUS, OR A COMPOUND THEREOF, IN AN AMOUNT OF 1.3 TO 6.6 WEIGHT PERCENT OF SAID XEROGEL CALCULATED AS PHOSPHORUS; (C) SILICA, IN AN AMOUNT OF 0.5 TO 13 WEIGHT PERCENT OF SAID XEROGEL; AND (D) ALUMINA, IN AN AMOUNT OF AT LEAST 30 WEIGHT PERCENT OF SAID XEROGEL.

United States Patent Office 3,682,836 Patented Aug. 8, 1972 US. Cl.252-437 9 Claims ABSTRACT OF THE DISCLOSURE A hydrotreating catalystconsisting essentially of a porous xerogel containing (a) tungsten, inthe form of metal, metal oxide, metal sulfide, or any combinationthereof, in an amount of to 25 weight percent of said xerogel,calculated as metal;

(b) discrete substantially insoluble metal phosphate particles (1) beingdispersed in said xerogel,

(2) consisting of at least one metal phosphate selected from phosphatesof titanium, zirconium, thorium, tin, hafnium and cerium, and

(3) containing phosphorus, or a compound thereof, in an amount of 1.3 to6.6 weight percent of said xerogel calculated as phosphorus;

(c) silica, in an amount of 0.5 to weight percent of said xerogel; and

(d) alumina, in an amount of at least 30 weight percent of said xerogel.

RELATED APPLICATIONS This application is a continuation-in-part ofJoseph Jaffe application Ser. No. 843,207, filed July 18, 1969, now USPat. 3,516,927, which in turn is a continuationin-part of Joseph Jaifeapplication Ser. No. 671,994, filed Oct. 2, 1967, now US. Pat.3,493,517.

STATEMENT OF INVENTION (a) nickel or cobalt, or the combination thereof,in the form of metal, oxide, sulfide, or any combination thereof, in anamount of 1 to 10 weight percent of said xerogel, calculated as metal,

(b) tungsten, in the form of metal, oxide, sulfide, or any combinationthereof, in an amount of 5 to 25 Weight percent of said xerogel,calculated as metal,

(0) a tetravalent metal or compound thereof selected from the group ofmetals consisting of titanium, zirconium, thorium, tin, hafnium, cerium,and compounds of said metals, in an amount of 3 to 12 weight percent ofsaid xerogel, calculated as metal,

(d) phosphorus or a compound thereof, in an amount of 1.3 to 6.6 weightpercent of said xerogel, calculated as phosphorus,

(e) silica, in an amount of 0.5 to 10 weight percent of said xerogel;and

(f) alumina, in an amount of at least 30 weight percent, preferably 30to weight percent, more preferably 30 to 50 weight percent, of saidxerogel;

said xerogel having (a) a surface area above square meters per gram, (b)an average pore diameter above 40 angstroms, and (c) a porosity above 60volume percent;

macroscopic sections or fracture planes of pellets or other particles ofsaid xerogel having a homogeneous appearance.

In accordance with the present invention there is provided also acatalyst consisting essentially of a porous xerogel containing:

(a) nickel or cobalt, or the combination thereof, in the form of metal,oxide, sulfide, or any combination thereof, in an amount of 1 to 10weight percent of said xerogel, calculated as metal,

(b) tungsten, in the form of metal, oxide, sulfide, or any combinationthereof, in an amount of 5 to 25 Weight percent of said xerogel,calculated as metal,

(0) a tetravalent metal phosphate selected from phosphates of titanium,zirconium, thorium, tin, hafnium, and cerium, in an amount of 8 to 35weight percent of said xerogel, said tetravalent metal phosphate havinga metal-to-phosphorus atomic ratio of at least 1:2,

(d) silica, in an amount of 0.5 to 10 weight percent of said xerogel,and

(e) alumina, in an amount of at least 30 weight percent of said xerogel;

said xerogel having (a) a surface area above 100 square meters per gram,(b) an average pore diameter above 40 angstroms, and (c) a porosityabove 60 volume percent;

macroscopic sections or fracture planes of pellets or other particles ofsaid xerogel having a homogeneous appearance.

In accordance with the present invention there is provided also themethod of manufacturing a hydrocarbon conversion catalyst whichcomprises substantially uniformly dispersing metal phosphate particlesin a matrix comprising silica, alumina, and at least one hydrogenatingcomponent, said hydrogenating component being selected from tungsten andcompounds thereof and Group VHI metals, particularly nickel and cobalt,and compounds thereof.

In accordance with the present invention there is provided also themethod of manufacturing a hydrocarbon conversion catalyst consistingessentially of a metal phosphate, a solid oxide comprising silica andalumina, and a hydrogenating component, which comprises forming asuspension of substantially uniformly dispersed particles of said metalphosphate in a liquid comprising substantially uniformly dispersedprecursors of said solid oxide and of said hydrogenating component, andcausing said liquid to form a gel surrounding said particles of saidmetal phosphate.

In accordance with the present invention there is provided also themethod of manufacturing a hydrocarbon conversion catalyst whichcomprises forming particles of a substantially water-insoluble metalphosphate by reacting in an aqueous medium, comprising at least oneprecursor of at least one catalytic component of the final catalystother than a metal phosphate, a water-soluble phosphate with awater-soluble compound of a Group IV metal, adding to said medium, ifnot already present therein, a precursor of silica, a precursor ofalumina, a

tungsten compound and a Group VIII metal compound, particularly a nickelor cobalt compound, and causing gelation of said medium, whereby saidparticles are surrounded by a gel matrix.

In accordance with the present invention there is provided also themethod of preparing a hydrocarbon conversion catalyst consistingessentially of a metal phosphate, at least one solid oxide comprisingsilica and alumina, and at least one hydrogenating component, whichcomprises forming a hydrous gel comprising at least one precursor ofsaid solid oxide, and at least one precursor of said hydrogenatingcomponent, dispersing particles of a substantially water-insoluble metalphosphate substantially uniformly in said hydrous gel, and drying andcalcining said hydrous gel containing said phosphate particles toproduce said catalyst.

In accordance with the present invention there is provided also themethod of preparing a hydrocarbon conversion catalyst consistingessentially of a Group -IV metal phosphate, a solid oxide comprisingsilica and alumina and a metal or metal compound hydrogenatingcomponent, which comprises:

(a) forming a first mixture comprising water, an aluminum salt, and asalt selected from the group consisb ing of titanium salts and zirconiumsalts;

(b) adding to said mixture a soluble phosphorus compound at conditionsunder which addition of said phosphorus compound will causeprecipitation of particles selected from the group consisting oftitanium phosphate particles and zirconium phosphate particles, toproduce a second mixture comprising said particles;

(c) adding to said second mixture a salt precursor of said hydrogenatingcomponent to produce a third mix ture;

(d) converting said third mixture to a gelled mixture comprising acontinuous-phase gel matrix, comprising precursors of alumina, andprecursors of said hydrogenating component, surrounding said phosphateparticles;

(e) including asilicate compound in at least one of said first, second,third and gelled mixtures; and

(f) treating said gelled mixture to convert the salts in said matrix tooxides.

In accordance with the present invention there is provided also ahydrotreating process which comprises contacting a hydrocarbon oil withhydrogen under hydrotreating conditions in the presence of a catalystconsisting essentially of a porous xerogel containing a substantiallyuniform mutual interspersion of the components thereof, which componentscomprise nickel or cobalt, tungsten, a tetravalent metal phosphate,particularly titanium phosphate or zirconium phosphate, silica, andalumina.

In accordance with the present invention there is provided also ahydrodesulfurization process which comprises contacting asulfur-containing hydrocarbon oil with hydrogen underhydrodesulfurization conditions in the presence of a catalyst consistingessentially of a substantially uniform mutual dispersion of atetravalent metal phosphate, at least one solid oxide comprising silicaand alumina, at least one hydrogenating component selected from tungstenand compounds thereof, and at least one hydrogenating component selectedfrom the group consisting of Group VIII metals, particularly nickel andcobalt, and compounds thereof.

PRIOR ART Prior art hydrocarbon conversion catalysts are known thatcontain metal phosphates, for example: (a) catalysts comprising asupport impregnated with a soluble metal phosphate such as tungstenphosphate, rather than an insoluble metal phosphate; (b) catalystscomprising insoluble metal phosphates that are not discrete, selectivelyprepared, insoluble metal phosphate particles in a continuous-phasematrix of non-phosphate catalyst components, but that are miscellaneousphosphates that have resulted from a non-selective and indiscriminatereac- 4 tion of a soluble phosphorus compound with a plurality ofcatalyst component precursors; and (0) catalyst comprising insolublemetal phosphates and a catalyst support but not containing ahydrogenating component.

DETAILED DESCRIPTION General: The present invention is concerned withnovel hydrocarbon conversion catalysts consisting essentially ofphosphorus or a compound thereof, a tetravalent metal or a compoundthereof, at least one solid oxide comprising silica and alumina, and atleast one hydrogenating component, said hydrogenating component beingselected from tungsten and compounds thereof and Group VIII metals andcompounds thereof, and with methods of preparation and use of saidcatalysts. In accordance with a preferred embodiment of the presentinvention, said phosphorus and tetravalent metal are present as asubstantially insoluble tetravalent metal phosphate. The term insolubleas used herein means substantially insoluble in any aqueous liquidmedium at a pH below 8.

PREFERRED METAL PHOSPHATE-CONTAINING CATALYSTS OF THE PRESENT INVENTIONAND PREPARATION THEREOF (A) General (a) Utility: The catalysts haveutility in various hydrotreating reactions, and particularly areoutstanding as hydrodesulfurization catalysts.

(b) Bulk density: The catalysts generally have lower densities thansimilar catalysts that do not contain a metal phosphate. In general, thedensity and fouling rate of the catalysts decreases as the weight ratioof metal phosphate to other components of the catalyst rises. It ispreferred to maintain the metal phosphate content of the final catalystin the range of 8 to 35 weight percent of the total catalyst.

(B) Metal phosphate components and formation thereof (a) General: Themetal phosphate components are more particularly phosphates oftetravalent metals, especially zirconium, titanium, tin, thorium, ceriumand hafnium. The metal phosphate components may be preformed asinsoluble particles and then dispersed in a hydrous gel containingprecursors of the other catalyst components, or dispersed in a liquidmedium containing said precursors, after which said liquid medium isconverted to gel form. Alternatively, the metal phosphate components maybe formed in situ in a liquid medium containing precursors of the othercatalyst components, after which said liquid medium is converted to gelform. In any case, the metal phosphate particles may be prepared byreacting in an aqueous medium, preferably comprising a largestoichiometric excess of water, a watersoluble salt of one of theaforesaid tetravalent metals with a Water-soluble source of phosphateion.

(b) Excess of H 0 when metal phosphates prepared separately: When themetal phosphates are prepared separately, it is convenient to maintainsufficient water in the reaction mix so that the reactants will reactreadily and so that the reaction will go to completion. The excess wateralso is useful in enabling the resulting slurry to be readilytransportable.

(c) Water-soluble salt of tetravalent metal: The watersoluble salt ofthe aforesaid tetravalent metals may be any convenient salt. Forexample, the metal salt may be a metal chloride, oxychloride, nitrate,sulfate, acetate, iodide or bromine. As a further example, wherezirconium is the tetravalent metal, the water-soluble zirconium salt maybe any of the readily available zirconium salts such as zirconiumtetrachloride, zirconyl chloride, zirconium sulfate, zirconyl bromide,zirconium tetraiodide and zirconyl iodide.

((1) Water-soluble source of phosphate ion: The watersoluble source ofphosphate ion may be any watersoluble phosphoric acid or otherwater-soluble phosphorus compound, preferably in which the phosphorushas a valence of +5, that under the conditions of contact with thetetravalent metal salt will cause precipitation of metal phosphates.Such water-soluble sources of phosphate ion are those which will releaseP for example orthophosphoric acid, H PO (2H PO P O +3H O). Othersuitable water-soluble sources of phosphate ion include: ammoniumphosphate,

NH4H2PO4 P205 tetraphosphoric acid H P O13 (H P O 2P O 3H O') andmetaphosphoric acid, HPO (4HPO 2P O +2H O).

(e) Stoichiometric ratio of the soluble phosphorus compound to solubletetravalent metal compound: It is espe cially preferred to avoid anamount of soluble phosphorus compound in excess of that which willprovide sufficient phosphate ion to react with the soluble metalcompound. That is, it is preferred that the metal phosphate particles inthe final catalyst contain substantially the entire phosphate content ofthe entire catalyst. Any excess of soluble phosphorus compound may actas a catalyst poison. In general, the molar ratio P O :MeO (Me=Zr, Th,etc.) should not exceed 1:1, i.e., the metal-to-phosphorus atomic ratioshould be at least 1:2. Such ratio will insure the absence of excess P 0which might act as a poison in the final catalyst. Although it ispreferable not to use an excess of soluble phosphorus compound, it ispermissible to use an excess of the tetravalent metal compound, becausethat excess generally is not detrimental to the final catalyst.

(f) pH ranges to be observed. When the metal phosphate particles areseparately preformed and then added to a gel precursor of the othercatalyst components, or added to a liquid medium containing precursorsof said other components, the pH at which the addition is made is notcritical, except that it should be a pH of 8 or below. Above a pH ofabout 8, the phosphate ion would be hydrolyzed from the metal phosphateparticles, whereas at a pH below about 8, the metal phosphate particlesremain insoluble. However, when the insoluble metal phosphate particlesare formed in situ in an aqueous liquid medium containing precursors ofthe other catalyst components, it is important that the formation occurat a pH below about 3.0 and preferably at a pH below about 2.5, in orderthat the soluble phosphate ion source will react with the solubletetravalent metal salt, but not with those of said precursors that aresoluble only at a pH below about 3.0. That is, it is important toobserve the indicated pH limitation in order to accomplish a selectiveprecipitation of the desired insoluble metal phosphate particles beforeprecipitation of the other catalyst components occurs. Onceprecipitation of the insoluble metal phosphate particles has occurred inthe liquid medium containing precursors of the other catalystcomponents, the pH thereafter may be raised to cause gelation orprecipitation of said precursors in which the insoluble metal phosphateparticles are substantially uniformly distributed, without affecting thecharacter of the insoluble metal phosphate particles, because onceformed those particles remain insoluble and will not dissociate at a pHup to about 8.

It will be noted that if the catalyst components that are not metalphosphates were first precipitated, and then were combined with asoluble phosphorus compound such as orthophosphoric acid, the phosphoruscompound could react indiscriminately with components in addition to thesoluble salts of the tetravalent metals that are intended to beconverted to insoluble metal phosphates, for example with any aluminumsalts and nickel salts that might be present. It is preferred to avoidsuch an indiscriminate reaction.

(C) Non-metal phosphate catalyst components and formation thereof (a)General: As previously indicated, and as will be further apparent fromthis Section C and from the examples herein after set forth, thecatalyst components of the catalyst of the present invention that arenot metal phosphates may be formed in a substantially uniforminterspersion thereof with the metal phosphate particles by: (1) beingformed as a hydrous gel into which preformed phosphate particles aredispersed after formation of said gel; or (2) being formed as an aqueoussolution, in which preformed metal phosphate particles are dispersed,followed by gelation of said solution around said particles; or (3)being formed first in part as a liquid medium in which the metalphosphate particles are formed by reaction of a soluble metal salt and asoluble phosphorus compound, followed by addition to said liquid mediumof additional catalyst components, followed by gelation of the resultingliquid medium.

(b) Excess of H 0: It is desirable in any liquid medium comprisingprecursors of the final non-phosphate catalyst components to maintain alarge excess of water, preferably suflicient to maintain the solidscontent in the liquid medium below 10 weight percent and more preferablyin the range 3 to 5 weight percent. Such a large excess of water willfacilitate intimate mixing of the reactants and will insure that whenthe liquid is precipitated it will be readily stirrable. Additionally,because it is desirable to remove certain soluble salts from theresulting gel, and because such removal is conveniently accomplished byfiltration and washing, a large excess of water during gel formationwill facilitate removal of a maximum quantity of salts during the firstfiltration, thus facilitating subsequent washing steps.

(0) At least one solid oxide: The final catalyst comprises at least onesolid oxide comprising silica and alumina. Those skilled in the art willeasily be able to select the appropriate precursor compounds suitablefor producing the desired solid oxides. The precursor of the aluminaconveniently may be aluminum chloride. The precursor of the silicaconveniently may be sodium silicate.

(d) At least one hydrogenating component: The final catalyst compositioncomprises at least one hydrogenating component selected from tungstenand compounds thereof and Group VIII metals, particularly nickel andcobalt, and compounds thereof, and preferably comprises both tungsten ora compound thereof and a Group VIII metal or compound thereof. Thetungsten component will be present in the final catalyst in an amount of5 to 25 weight percent thereof, calculated as metal. The Group VIIIcomponent will be present in the final catalyst in an amount of 1 to 10weight percent thereof, calculated as metal. Those skilled in the artwill easily be able to select the appropriate precursor compoundsuitable for .producing the desired hydrogenating component. Suitableprecursors for the tungsten hydrogenating component of the finalcatalyst include tungstic acid, sodium tungstate and ammonium tungstate.Suitable precursors for the Group VIII hydrogenating component of thefinal catalyst in clude the chlorides, acetates and nitrates of nickeland cobalt. It is preferable that nickel or a compound thereof andtungsten or a compound thereof be present in the final catalyst when itis to be used as a desulfurization catalyst. Catalysts preparedaccording to the process of the present invention that comprise nickelor a compound thereof and tungsten or a compound thereof areparticularly outstanding hydrodesulfurization catalysts.

(D) Catalyst filtering, drying, washing, activating, reducing andsulfiding (a) Filtering, drying and washing: Following gelation of allof the catalyst components, the resulting gel precipitate in the form ofan aqueous slurry is separated from the liquid portion of the slurry byfiltration in a conventional manner and'the precipitate is washed anddried 7 in a conventional manner. The drying may be accomplished in anoven at temperatures which conveniently may be between 200 and 300 F.for a time suflicient to produce adequate drying, for example 10 to 20hours.

The precipitate may be washed until the material is free of undesiredcontaminants in the form of soluble salts. Particularly where a sodiumsalt such as sodium tungstate has been used to prepare the catalyst orwhere chloride ion from metal chlorides is present, the wash waterdesirably will contain an ammonium salt such as ammonium acetate toassist in the ion-exchange removal of these impurities. A number ofseparate washes will be found desirable, including a final wash withwater, after which the washed material may be dried in the previousmanner.

(b) Activating: The resulting washed and dried material is activated ina conventional manner, for example by calcination for 2 to 6 hours indry air or other non-reducing gas at 800 to 1200 F., to produce thefinal catalyst in oxide form.

Reducing and sulfiding: Following calcination, the hydrogenatingcomponent or components of the catalyst may be converted at least inpart to metal form or sulfide form.

The calcined catalyst may be reduced and sulfided in a conventionalmanner, for example by treating it at a temperature of 500 to 700 F. inhydrogen gas containing H 8 or a precursor thereof such as dimethyldisulfide, for a :period of time suflicient to accomplish substantialconversion of the hydrogenating component or components to metalsulfides.

CATALYST USE (A) General: As already indicated, the catalysts of thepresent invention are outstanding hydrodesulfurization catalysts.

(B) Hydrodesulfurization process operation: The bydrodesulfurizationprocesses utilizing the catalysts of the present invention -may becarried out at conventional hydrodesulfurization process conditions, forexample at temperatures in the range 500 to 800 F., pressures in therange 200 to 10,000 p.s.i.-g., LHSVs based on the hydrocarbon oil feed,in the range 0.2 to 10, and at hydrogen rates of 500 to 20,000 s.c.f. ofhydrogen per barrel of hydrocarbon oil feed. A hydrodesulfurizationprocess conducted under these conditions with the catalyst of thepresent invention will effect the removal of a substantial proportion ofthe sulfur compounds contained in a wide variety of hydrocarbonfeedstocks, for example hydrocarbon distillates such as crackednaphthas, light cycle oils, coker distillates, straight-run gas oils,and residual hydrocarbon feedstocks.

EXAMPLES The following examples will serve to further illustrate thecatalysts of the present invention and their preparation and use:

EXAMPLE 1 A catalyst containing nickel, tungsten, titanium, phosphorus,alumina and silica (Catalyst A, a catalyst for use in the process of thepresent invention) was prepared by the following general procedure:

(a) an aqueous solution comprising aluminum chloride, titaniumtetrachloride, and acetic acid was prepared;

(b) titanium phosphate particles were caused to precipitate from saidsolution by combining said solution with a second aqueous solutioncontaining phosphoric acid, resulting in a slurry containing saidtitanium phosphate particles;

(c) an aqueous nickel chloride solution was added to said slurry to forma nickel-containing mixture;

(d) an aqueous solution of sodium silicate was added to saidnickel-containing mixture to form a silica-containing mixture;

(e) aqueous solutions contaim'ng ammonia and sodium ammonium tungstatewere added to said silica-containing mixture, causing coprecipitation ata pH of 7 to 7.5 of soluble metals not previously precipitated; (f) theresulting slurry was filtered to produce a filter cake, which was washedfree of soluble ions, dried and calcined, to produce the final catalyst.

EXAMPLE 2 A catalyst containing nickel, titanium, phosphorus, silica andalumina, but containing molybdenum instead of tungsten (Catalyst B, acomparison catalyst) was prepared by suitable modification of thegeneral procedure of Example 1.

(EXAMPLE 3 A catalyst containing nickel, molybdenum and alumina,titanium and phosphorus, with no silica or tungsten (Catalyst C, acomparison catalyst), was prepared by suitable modification of thegeneral procedure of Example 1.

COMPOSITION AND CHARACTERISTICS OF CATALYSTS A, B AND 0 Catalyst A(Ex. 1) B (Ex. 2) 0 (Ex. 3)

BET surface area, mfl/g 330 294 261 Particle density, g./cc 1. 69 1.74 1. 08 Average pore diameter, A 46 44 100 Porosity, ce./cc 0. 635 0.557 0. 707 Pore volume, cc./g 0.376 0.820 0. 655 Components and amountsthereof as weight percentages of catalyst:

Ni (NiO) 8 (10. 2) 8 (10.2) 8 (10.2) W (W03 2 (25.2) Mo (M003). 20 20(30) 'IiO 10 10 10 A1203 45 40 44. 5 SiOz.-. 4. 5 4. 5 P205 5 5 5 Thefollowing examples will serve to further illustrate the process of thepresent invention.

Two separate portions of an Arabian Atmospheric Residuum hydrocarbonfeedstock were separately hydrodesulfurized in the presence of CatalystsA and B of Examples 1 and 2, respectively, at identical conditions. Thehydrocarbon feedstock had the following characteristics:

Total hydrogen rate, s.c.f./bbl. 10,000

Product sulfur, weight percent 0.5

Starting temperature needed to maintain indicated product sulfur level(See below) The hydrodesulfurization results were as follows:

Catalyst Starting temperature, F 743 717 Catalyst fouling rate, F./l1r0. 01 0. 04

EXAMPLE 5 Two additional separate portions of the same Arabian LightAtmospheric residuum used in Example 4 were separately hydrodesulfurizedin the presence of Catalysts A and C of Examples 1 and 3, respectively,at identical conditions. The conditions were:

Space velocity, v./v./hour 0.8 Total pressure, p.s.i.g 800 Totalhydrogen rate, s.c.f./bbl. 2,000 Product sulfur, weight percent 1.0Starting temperature needed to maintain indicated product sulfur level(See below) The hydrodesulfurization results were as follows:

Catalyst Starting temperature, F Catalyst fouling rate, F./hr

(a) molybdenum and silica, but no tungsten, or (b) molybdenum, but notungsten or silica.

That is, referring to Catalysts A, B and C of Examples It is apparentthat, with respect to hydrodesulfurization catalysts containing nickel,phosphorus and alumina, there is a surprising synergistic effect amongat least some of the components thereof when the catalysts also containsilica and tungsten, but no molybdenum, that results in an unexpectedlylow fouling rate compared with similar catalysts that contain molybdenumbut no tungsten, regardless of wthether those similar catalysts alsocontain silica.

What is claimed is:

1. A catalyst consisting essentially of a porous xerogel containing:

(a) tungsten, in the form of metal, oxide, sulfide, or any combinationthereof, in an amount of 5 to 25 weight percent of said xerogel,calculated as metal;

(b) discrete substantially insoluble metal phosphate particles (1) beingdispersed in said xerogel,

(2) consisting of at least one metal phosphate selected from the groupconsisting of phosphates of titanium, zirconium, thorium, tin, hafnium,and cerium, and

(3) containing phosphorus, in an amount of 1.3 to 6.6 Weight percent ofsaid xerogel calculated as phosphorus;

(c) silica, in an amount of 0.5 to weight percent of said xerogel; and

(d) alumina, in an amount of at least 30 weight percent of said xerogel.

2. A catalyst composite as in claim 1 wherein the catalyst furthercontains a Group VIII metal, metal sulfide, or metal oxide.

3. A catalyst composite as in claim 1 wherein the composite furthercontains nickel in the form of metal, oxide, sulfide or any combinationthereof or cobalt in the form of metal, oxide, sulfide or anycombination thereof.

4. A catalyst consisting essentially of a porous xerogel containing:

(a) nickel, cobalt, or the combination thereof, in the form of metal,oxide, sulfide, or any combination thereof, in an amount of 1 to 10weight percent of said xerogel, calculated as metal,

(b) tungsten, in the form of metal, oxide, sulfide, or any combinationthereof, in an amount of 5 to 25 weight percent of said xerogel,calculated as metal,

(c) discrete substantially insoluble metal phosphate particles,

(1) being dispersed in said xerogel,

(2) consisting of at least one metal phosphate selected from the groupconsisting of phosphates of titanium, zirconium, thorium, tin, hafniumand cerium, and

(3) containing phosphorus in an amount of 1.3 to 6.6 weight percent ofsaid xerogel calculated as phosphorus;

(d) silica, in an amount of 0.5 to 10 weight percent of said xerogel;and

(e) alumina, in an amount of at least 30 weight percent of said xerogel;

said xerogel having (a) a surface area above square meters per gram,

(b) an average pore diameter above 40 angstroms,

and

(c) a porosity above 60 volume percent; macroscopic sections or fractureplanes of pellets or other particles of said xerogel having ahomogeneous appearance.

5. A catalyst as in claim 4, wherein said metal phosphate is present insaid xerogel in an amount of 8 to 35 weight percent thereof and whichhas a metal-to-phosphorus atomic ratio of at least 1:2.

6. The method of manufacturing a hydrocarbon conversion catalyst, saidcatalyst being in accordance with claim 1, which comprises substantiallyuniformly dispersing metal phosphate particles in a matrix comprisingsilica, alumina, and at least tungsten, tungsten sulfide, or tungstenoxide as a hydrogenating component.

7. The method as in claim 6, wherein said catalyst consists essentiallyof a metal phosphate, a solid oxide comprising silica and alumina, andat least tungsten, tungsten sulfide, or tungsten oxide as ahydrogenating component, and wherein said particles are dispersed insaid matrix by forming a suspension of substantially uniformly dispersedparticles of said metal phosphate in a liquid comprising substantiallyuniformly dispersed precursors of said solid oxide and of saidhydrogenating component, and causing said liquid to form a gelsurrounding said particles of said metal phosphate.

8. The method as in claim 6 wherein said metal phosphate particles areformed by reacting, a water-soluble compound of a Group IV metal withphosphorus or a phosphorus compound, and wherein said particles are dispersed in said matrix by adding to said medium, if not already presenttherein, a precursor of silica, a precursor of alumina, a tungstencompound and a Group VIII metal compound, and causing gelation of saidmedium, whereby said particles are surrounded by a gel matrix.

9. The method of preparing a hydrocarbon conversion catalyst, saidcatalyst being in accordance with claim 1, and consisting essentially ofa Group IV metal phosphate, a solid oxide comprising silica and aluminaand tungsten, tungsten sulfide, or tungsten oxide as a hydrogenatingcomponent, which comprises:

(a) forming a first mixture comprising water, an alumi- 11 num salt, anda salt selected from the group consisting of titanium salts andzirconium salts;

(b) adding to said mixture a soluble phosphorus com- (c) adding to saidsecond mixture a salt precursor of 10 said hydrogenating component toproduce a third mixture;

(d) converting said third mixture to a gelled mixture comprising acontinuous-phase gel matrix, comprising precursors of alumina, andprecursors of said 15 hydrogenating component, surrounding saidphosphate particles;

(e) including a silicate compound in at least one of said first, second,third and gelled mixtures; and

(f) treating said gelled mixture to convert the salts in said matrix tooxides.

References Cited UNITED STATES PATENTS 3,493,517 2/1970 Jafie 2524373,544,452 12/1970 Jalfe 208216 P C G R im r xam ne A US. Cl. XR.

